This patent application claims priority to Swedish Patent Application Number 9903509-9 filed Sep. 27 1999. The full disclosure of said application, in its entirety, is hereby expressly incorporated by reference into the present application.
The present invention relates to an antenna unit for receiving electromagnetic signals in a vehicle. The unit comprises two or more antennae and two or more tuner units, which are each connected to at least one of the antennae.
Concurrently with the rapid development of communication techniques, the need for receiving and/or transmitting electromagnetic signals of different types in a vehicle increases all the time. This involves, for example, analog and/or digital radio, analog and/or digital TV, mobile telephony, navigation and security information.
To receive these and similar type signals, an increasing number of antennae are mounted in vehicles, usually one antenna for each function. Each such antenna is normally placed in a position which is suitable for the specific antenna: for example, ordinary rod antennae are fixed to the body of the vehicle, wire antennae are cast into the windowpanes, and monopole antennae in the form of plates are mounted in the bumpers of the vehicle.
To mount a plurality of different antennae in a vehicle, a number of mounting steps are necessary and which are both time-consuming and expensive.
When antennae are mounted in windowpanes, there is a conflict: on the one hand, there is the effect of the glass on the receiving properties of the antenna and, on the other hand, there is the climate-protecting properties of the glass. There may be, for example, limitations as to the thickness of the glass because of the radio antenna being cast into the windowpane.
Moreover, each antenna is typically connected to a receiver(tuner) by means of e.g., a coaxial cable. This can result the signal quality decreasing if the distance is too great which is a notable inconvenience. To remedy this inconvenience, antenna boosters are arranged along the extent of the coaxial cable, but this is complicated and makes the installation expensive and does not completely remedy the problem.
In order to avoid long cables between antenna and tuner, tuners can be arranged in direct connection with the antenna. There is, however, still the inconvenience of antennae that are arranged in various positions about the vehicle.
Another problem is that the signal requirements change all the time; these changes being at least partially dependent on which part of the world the vehicle is being used and on the needs of the individual driver/passenger. With known techniques, it is relatively complicated to install an extra antenna, for example, for utilization with GPS navigation in an existing vehicle. Among others, complicating reasons include required modifications to mount the antenna, as well as connect the antenna by means of a cable to the tuner which may be arranged at the other end of the vehicle.
For antennae that are mounted in the windowpanes of the vehicle, the need for an additional antenna may cause a change of windowpane.
In view of the above described deficiencies associated with the implementation and use of known antennae designs, the present invention has been developed to alleviate these drawbacks and provide further benefits to the user. These enhancements and benefits are described in greater detail hereinbelow with respect to several alternative embodiments of the present invention.
The present invention in its several disclosed embodiments alleviates the drawbacks described above with respect to conventionally designed antenna units and incorporates several additional beneficial features.
Among the several objects of the present invention, one is to enable a joint assembly of several antennae and tuners. Another is to eliminate the need for long coaxial cables that connect the antennae and tuners, and thus eliminate the need for antenna boosters. Yet another is to provide a cost-efficient mounting of antennae when a large number of antennae is required.
According to the present invention, these objects are achieved by an antenna unit of a type, stated by way of introduction, which is characterized in that the output signals from the tuner units are connected to a common coordinating means, arrangement or unit. The antennae, tuner units and coordinating means are arranged on a common supporting element to form an integrated unit. An output signal from the coordinating means, via a communication interface, is connectable to a vehicle-internal communication path.
Several antennae can thus be arranged on a common supporting element which is then mounted in the vehicle. By arranging the receivers (tuners) in connection with the antennae on the same supporting element, the need for long lines between antenna and tuner is eliminated. At the same time, the mounting of antennae and tuners is further simplified. By the output signals from several tuners being multiplexed by the coordinating means, a multiplexed signal can be made available on an internal communication path of the vehicle. When the antenna unit has been mounted in the vehicle, only a connection to the communication path is thus required for a plurality of received signals to be available all over the vehicle.
The communication path is suitably a databus of known design, which may comprise, for example, an optical cable.
An antenna can be connected to several tuners, and a tuner may be connected to several antennae. The connection which is most convenient is determined by the properties of the antennae and the signals which are to be received.
According to a preferred embodiment, antennae and tuner units are releasably arranged on the supporting element. This facilitates mounting and replacement of antennae and tuner units, while at the same time permitting adaptation of such an antenna module to different configurations and markets.
Each antenna and each tuner which is arranged on the printed circuit board can thus be removed or changed in one simple operation. A vehicle that, on delivery, is not equipped with an antenna for receiving a signal of a certain kind, can in a simple operation be provided with this antenna and the corresponding tuner. Thus the signal is made available on the internal databus of the vehicle and can be arranged in a suitable position, for example where equipment utilizing the signal at issue is mounted.
In particular this modularized antenna unit is suitable when each antenna is relatively expensive, which is the case, for example, with GPS antennae and satellite radio antennae.
Since many antenna categories, such as radio or TV antennae, require a relatively large space in at least two dimensions, antennae of this type are suitably fixedly arranged on the supporting element.
According to a preferred embodiment, the supporting element includes a planar sheet of a non-conductive material, for example plastic, in order to interfere as little as possible with the reception. The sheet can be mountable in a plane proximate the body on the upper side of the vehicle. This arrangement of the antenna unit is advantageous owing to its great distance to the roadway as well as to the engine, both of which may cause interference in the reception. By this embodiment of the invention, a superior alternative to arranging antennae in the windowpanes of the vehicle is provided.
If the body of the vehicle is made of a conductive material, the antenna unit is suitably mountable in a recess in the body. This prevents capacitance from arising between antennae and the conductive vehicle body.
The beneficial effects described above apply generally to the exemplary devices and mechanisms disclosed herein for an antennae arrangement. The specific structures through which these benefits may be delivered will be described in detail hereinbelow.